Layer 5 - The session layer

The primary purpose of the session layer is to coordinate and synchronize the dialog between the presentation layers at the two end points and to manage their data exchange. This layer establishes, manages, and terminates connections between applications. The session layer sets up, coordinates, and terminates conversations, exchanges, and dialogues between the applications at each end.

Some of the protocols operating at the session layer are sockets, NetBIOS, SAP, SOCKS, RPC, and so on.